Visual aid technique of presenting drawing changes



Dec. 15, 1964 E. GOSMANN 3,151,510

VISUAL AID TECHNIQUE OF PRESENTING DRAWING CHANGES Filed Oct. 26, 1961 2 Sheets-Sheet 2 /E RR-C 122GB ao X X 9 I a a rd 570 F! g! m m m N ;IEI:P 5 a: mmmmm In P g 95" a Mama .1

20AM XX XX gggm8 -wmw]%@ a (Msol) uloss @Qmmrwmvmmoo- -ooo cpo 20AM u 9%.. 35 m5 oom'm um% --:nl r mmmlm m INVENTOE E.GOSMANN ATTORNEY United States Patent p 3 161 510 vrsnar. An) rncnnrdun or PRESENTING DRAWING CHANGES, Enart Gosmann, Hinsdale, BIL, assignor to Western Elect' ic Company, Incorporated, a corporation of New orlr ' Filed Oct. 26, 1961, Ser. No. 147,951

7 2 Claims. (Cl. 96-43} The present invention relates generally to visual aid techniques of presenting drawing changes, and more particularly to methods of making drawing changes and producing prints which illustrate the original system faintly but distinctly while pinpointing the changes which have been made. Accordingly, the generally objects of the invention are to provide new and improved methodsiof such character. V 1

In the telephone industry, there are millions of equipment engineering drawings, largely electrical schematics,

- relating to the construction and operation of telephone exchanges and other equipment.

Inasmuch as this industry is one in WhICh continuing change, expansion and modification of equipment and circuits'is the normal routine of business, there are in excess of one-half million drawing changes made each year in the Bell System by equipment engineers centered at different locations.

The conventional method ofhandling the drawings in the first instance is to prepare suflicient Van Dyke negae 3,161,516 Patented Dec. 15, 1964 so as to require considerable time and effort both on the part of the engineer preparing the descriptive memorandum and on the part of the field personnel in studying the three documents. Another major object of the present invention is to provide two tone prints in this situation, on which the original drawing appears faintly but distinctly and on which markings indicating the changes to be made are much darker and thus stand out so as to indicate at a glance the changes to be made. This technique obviates the requirement of a descriptive memorandum in almost all cases and also eliminates the need for the field personnel to read a copy of the original drawing to understand the changes; all information needed is presented at once and on one drawing.

.With the foregoing and other more specific objects in view, the first step in making drawing changes in accordance with the invention is to reproduce the original drawing on transparentized paper to obtain a positive transparency of the original drawing by a special blueprinting process from a negative of the original tracing, preferably where a portion of the blueprint coating is applied to each side of the transparentized paper. After this has been done, the engineer illustrates the changes to be made by drawing on the face of the positive transparency, pref erably with a heavy pencil but optionally with ink or wax crayon, in such a manner and according to a code where necessary to provide markings which clearly indicate the changes in the drawing. Finally, as many positive prints as needed are produced from the marked positive transparency, one copy being forwarded to the drafting or-, ganization for the preparation of a new original drawing at whatever time may be convenient, and further copies 7 being sent to the field personnel who may then begin ganization. The draftsman would then make the indicated changes on the original tracing, thereby producing a new issue of the drawing. A Van Dyke print. and blueprints would then be made from the new tracing and shipped out to the various interested persons in the field, together with copies of the memorandum describing the drawing changes.

While this technique has served very well for a great many years, there are certain inherent problems and inefiiciencies involved in that method, as compared with the subject method. The two primary drawbacks to the prior method relate. to (1) time and (2) comprehension.

(l) T ime.,'An average delay of several weeks, based on the quite variable drafting load at any moment, has

been required in the past to gctthe needed information into the field,.where it is usually desired at once. other important object of the invention is to provide a method ofmaking drawingv changes wherein as many copies as are needed of marked prints illustrating the changes may be shipped immediately from the engineer to the field personnel without waiting for redrafting of the original tracing. With this arrangement, a related objective is realized in that there is no longer any necessity to. reissue the original drawing at the earliest possible moment, and the draftingwork load may thus be equal- (2) Comprehension.wParticularly where thef drawing changes are many and varied, and especially in large elec- "trical circuit drawings, it has in most cases been necessaryfor those field personnelm'aking the changes and and cannot depict in detail what is old-as opposedto what is new, the changes being buried in the new drawing working immediately on the system. The relative opacity of the reproduced lines of the original drawing and the added pencil markings are such that the original drawing'appears on the positive prints faintly but distinctly, while the added markings appear much darker thus standing out so as to indicate at a glance the changes to be made.

Other objects, advantages and aspects of the invention will be apparent by reference to the following detailed description of a specific embodiment thereof, when taken in conjunction with the appended drawings, in which:

FIG. 1 is a flow diagram indicating the sequence of steps to be followed in practicing the invention; and

FIG; 2 is an illustration of a final marked print produced in accordance with the invention.

Referring now in detail to the drawings, and particularly to FIG. 1, boxes 10-, 11 and 12 illustrate the conventional steps followed both in the prior method and with the present invention to produce and distribute copies of the original tracing. Thus, the numeral 10 designates the original tracing, the numeral 11 designates one of several Van Dyke negatives (iron-silver brownprin ts), whichare prepared from the original tracing and are distributed to the various equipment engineering 10- cations, and the numeral 12 indicates one of, several working blueprints which are prepared from the Van Dyke negatives.

Using the prior method'of making drawing changes, as indicated with light lines at the left of FIG. 1, the engineer indicated the changes in colored pencil on a blueprint and forwarded the marked blueprint 20, as indicated. by arrow A, to the drafting organization which then prepared a new tracing 10 from the original. Van Dyke negatives 11 and blueprints 12' of the-new tracing 10' were then prepared and distributed to the field personnel, who in most cases were required to compare the new blueprint 12' with a copy of the old blueprint 12 g In contrast with this procedure, and in accordance with the present techniques, the engineer prepares a positive transparency from the Van Dyke print 11, marks the transparency 30 with pencil so as to indicate the changes to be made, and produces several positive prints 31--31 from the marked transparency 30. The positive prints 31-31 may be produced in any conventional manner from the marked transparency 30, and preferably are either full scale, black and white prints-or microfilms. The positive prints 31 are sent at once to the field personnel, and one copy (arrow B) is recycled to the drafting organization which then reissues the original drawing as in accordance with the prior method.

FIG. 2 is a representation of a two tone marked positive print prepared in accordance with the invention, in which the reproduced lines 35-35 of the original drawing appear faintly but distinctly, while the added markings 3636, indicating the changes to be made, are much darker and thus stand out so as to indicate .clearly and at a glance the changes which were made. 1

As far as is presently known, blueprints have never before been produced commercially on transparentized paper, since the blueprint has always been the final working drawing and it would be quite undesirable to use transparent paper because of the increased cost and because the reproduction would not be as good. However, it should be appreciated that in the present application the transparent blueprint is only an intermediate print and is not the working drawing. In this application, it is specifically desired to produce a print which, while clear, is intentionally faint.

The blueprinting process used is essentially the conventional blueprinting process which has been standard for over a hundred years, wherein the paper is coated with a solution containing potassium ferricyanide and ,ferric ammonium citrate or oxalate and dried in the dark.

When this paper is exposed to light through a master having transparent and opaque areas, the ferric ions are re- .duced by the light to the ferrous state wherever the light passes through the master drawing and strikes the paper.

The treated paper is developed by a water treatment whereupon the ferrous and ferricyanide ions interact to form insoluble Turnbulls blue, ferrous ferricyanide, wherever the ferrous salt was produced by light. On other .points on the paper where there has been no reduction blueprint.

With regard to the transparentized paper, the word transparent is used in the photographic sense and more specifically refers to a translucent paper having an opacity such that further prints may be made by transmitting light through the paper.

Ordinary paper is a fibrous cellulose material having air occluded between the fibers, and is not optically homogeneous; therefore,-it appears opaque even in thin layers unless specially treated. in order to make the paper pervious to light, these spaces between the fibers must be filled with a material that transmits light to approximately the same degree as the cellulose fibers. The light transmittance of a material is known as its refractive index (RI) and for cellulose varies from about 1.53 to 1.59. Various resinous materials, oils and waxes having a RI within or close to this range are prior known for transparentizing paper. Various transparentized papers are available commerically, on which pencil markings may be made, one such being a high translucency type of paper used for making Van Dyke prints, Catalog No. 158 paper manufactured by the Charles Bruning Company, Inc., of Mount Prospect, Illinois. This paper is a rosin-transparentized, 100% rag content paper.

One important facet of the invention relates to the relative amount of blueprint coating to be used, which in most instances is significantly less (more dilute than in ordinary blueprinting processes where the blueprint is the final image and is to be as clear as possible. The most important criterion in determining the correct amount is to be certain to obtain a positive black and white print (or microfilm where the original drawing appears somewhat faintly but quite distinctly, as a ghost image. The amount of coating may be adjusted in practice, based on any particular brand of paper and blueprint coating utilized, to produce optimum results.

While it is quite feasible to practice the invention with the entire blueprint coating applied to the front side of the transparentized paper (or to the back side alone), it has been determined that the best drawings are prepared when the paper is coated on both sides. Preferably, between 5 and 25% of the total blueprint coating is applied to the front side of the transparentized paper and the remainder of the blueprint coating is applied to the back side. It has beenobserved that the acuity of the final black and white print is greatly enhanced by the reverse coating. The amount of coating on the front side determines the visibility of the lines on the transparency so as to make it easier to read and correct.

When this procedure is followed, the added pencil markings are relatively opaque compared to the reproduced ines of the original drawing such that the added markings on the positive prints appear much darker and thus stand out, as is depicted in FIG. 2 of the drawings. While the selection of the pencil is ordinarily not critical, it must make a line which is significantly more opaque than the reproduced line of the original drawing. If necessary, ink or crayon may be used in place of the pencil, and the phrase pencil markings is intended to include such equivalents.

The positive black and while prints are produced by the well-known diazotype processes commonly applied to produce a positive print from a positive transparency. The diazotype coating is sensitive primarily to violet and ultraviolet light, whereby the blue lines of the positive transparency tend to transmit some light and thus show faintly while the added pencil lines are jet black and transmit no light so that they reproduce jet black on the black and white print. Basically, the diazotype process, and the Van Dyke, blueprinting, and microfilming processes used in practicing the invention are all wellknown and standardized processes per se, further details of which may be obtained from standard reference texts, such as Photography, Its Materials and Processes by C. B. Neblette, 5th ed. (1952).

In view of the foregoing detailed description of a specific embodiment of the invention, it is apparent that a new and improved method of presenting drawing changes has been achieved wherein the engineer may quickly and easily indicate the changes to be made by drawing on the face of the positive transparency with a pencil or other suitable implement, and may then make as many black or white or microfilm prints as are required from the transparency, so as to forward the information immediately to all parties concerned while recycling a copy to the draftsman for reissue of the original drawing in due course. It is clear that the comprehension is enhanced, since the added markings on the black and white print appear much darker so as to pinpoint the changes and render them obvious to the field personnel, thus substantially eliminating the requirement of comparing new and old drawings in light of a descriptive memorandum stating the changes.

While one specific embodiment of the invention has been described in detail hereinabove, it will be obvious that various changes may be made from the specific details described without departing from the spirit and scope of the invention.

What is claimed is:

1. The method of presenting drawing changes, which method comprises the steps of:

preparing a negative print from the original drawing; preparing a positive transparency from a single exposure of a transparentized blueprint paper to the negative print, the transparentized blueprint paper being pretreated on both sides thereof with a relatively dilute solution of blueprint coating such that the image on the negative print will be reproduced on both sides of the positive transparency; drawing only on one side of the positive transparency with a pencil in such a manner as to provide markings clearly indicating the changes in the image reproduced on the positive transparency; and producing positive prints from the marked positive transparency; the relative opacity of the image reproduced on the positive transparency and the pencil markings added thereto being such that upon production of the positive print markings representative of the original drawing reproduce faintly but distinctly, while markings representative of the added markings reproduce much darker and thus stand out as to indicate at a glance the changes that were made. 2. The method as recited in claim 1 wherein 5 to 25% of the relatively dilute blueprint coating is applied to one side of the transparentized paper and the remainder thereof is applied to the other side and wherein the pencil markings are made on the one side coated with the 5 to 25% of the relatively dilute blueprint coating.

References Cited in the file of this patent UNITED STATES PATENTS 1,112,450 Hess Oct. 6, 1914 1,213,925 McCloskey Jan. 30, 1917 2,158,422 Holden May 16, 1939 2,253,562 Hinman et a1. Aug. 26, 1941 2,317,521 Crowley et a1 Apr. 27, 1943 2,341,877 Middleton et a1 Feb. 15, 1944 2,501,874 Peterson Mar. 28, 1950 2,801,919 Eichorn Aug. 6, 1957 2,931,724 Lantz Apr. 5, 1960 OTHER REFERENCES Hackleman: Commercial Engraving and Printing, published by Commercial Engraving Publishing Co., 1924, pages 117-120, 127 and 128 relied on.

Eugene Ditzgen Co. Catalogue entitled Reproduction Materials, page 25.

American Machinist, volume 101, Aug. 26, 1957, page 105.

Chemical Engineering, vol. 65, May 19, 1958, pages 161-165.

Helios, Keuifel & Esser Co., 1947. Copy may be seen in 96-91. A photocopy will not show all of the properties of this reference. The pages headed Helios natural transparent paper and Helios tracing cloth and the transparent and tracing papers sepia lines 498 and 518 are particularly noted. 

1. THE METHOD OF PRESENTING DRAWING CHANGES, WHICH METHOD COMPRISES THE STEPS OF; PREPARING A NEGATIVE PRINT FROM THE ORIGINAL DRAWING; PREPARING A POSITIVE TRANSPARENCY FROM A SINGLE EXPOSURE OF A TRANSPARENTIZED BLUEPRINT PAPER TO THE NEGATIVE PRINT, THE TRANSPARENTIZED BLUEPRINT PAPER BEING PRETREATED ON BOTH SIDES THEROF WITH A REALATIVELY DILUTE SOLUTION OF BLUEPRINT COATING SUCH THAT THE IMAGE ON THE NEGATIVE PRINT WILL BE REPRODUCED ON BOTH SIDES OF THE POSITIVE TRANSPANENCY; DRAWING ONLY ON ONE SIDE OF THE POSITIVE TRANSPARENCY WITH A PENCILIN SUCH A MANNER AS TO PROVIDE MARKINGS CLEARLY INDICATING THE CHANGES IN THE IMAGE REPRODUCED ON THE POSITIVE TRANSPARENCY; AND PRODUCING POSITIVE PRINTS FROM THE MARKED POSITIVE TRANSPARENCY; THE RELATIVE OPACITY OF THE IMAGE REPRODUCED ON THE POSITIVE TRANSPARENCY AND THE PENCIL MARKINGS ADDED THERETO BEING SUCH THAT UPON PRODUCTION OF THE POSITIVE PRINT MARKINGS REPRESENTIVE OF THE ORIGINAL DRAWING REPRODUCE FAINTLY BUT DISTINCTLY, WHILE MARKINGS REPRESENTATIVE OF THE ADDED MARKINGS REPRODUCE MUCH DARKER AND THUS STAND OUT AS TO INDICATE AT A GLANCE THE CHANGES THAT WERE MADE. 